Typical probes used for signal acquisition and analysis devices such as digital storage oscilloscopes (DSOs) and the like have an impedance associated with them which varies with frequency. For example, a typical probe may have an impedance of 100K to 200K Ohms at DC, which impedance drops towards 200 ohms at 1.5 GHz. Higher bandwidth probes drop to even lower impedance values. This drop in impedance as frequency increases, coupled with the fact that many circuits being probed have a relatively low output impedance in the range of 25-150 ohms, results in a significant loading of the circuit under test by the probe. As such, an acquired waveform received via a probe loading such a circuit may not accurately represent the voltage of the circuit prior to the introduction of the probe.
There is also a further need to process acquired samples of a signal from a device under test to produce an output representing the impedance of the device under test. Such a capability in a signal analysis system would allow a user to observe the impedance of the device under test.